1. Field of the Invention
The present invention relates to a technique of reproducing color prints with an output device, such as a display device or a printer.
2. Description of the Related Art
In reproducing a color print with a variety of output devices including a display device and a printer, it is desirable to reproduce colors closest possible to those of the actual color print. The conventional method of reproducing colors of a print utilizes a known equation, such as Marley-Davis's Equation, Jule-Nielsen's Equation, or Neugebauer's Equation. For example, Neugebauer's Equation is used to calculate the values of color components R, G, and B from the dot percents of four color inks Y, M, C, and K.
The known conversion equations are, however, based on an ideal model and can not reproduce the actual colors in many cases. Especially, no model is applicable for simulating observation of a print arranged in a three-dimensional space.
The applicant of the present invention has proposed a method of reproducing a print arranged in a three-dimensional space, as disclosed in U.S. Pat. No. 5,596,425. This proposed method determines an illuminance spectrum I(.theta., .rho., .lambda.) of reflected light from a color print according to a specular reflection coefficient Ss(.lambda.) and an internal reflection coefficient Sb(.lambda.), and displays the color print based on the illuminance spectrum I(.theta., .rho., .lambda.), where .theta. denotes an angle of reflection, .rho. denotes an angle of deviation, and .lambda. denotes a wavelength. This method can faithfully reproduce a print having a specific dot percent, such as 100%, of a single primary color, but it requires the values of the reflection coefficients Ss(.lambda.) and Sb(.lambda.) for the entire range of the dot percent in reproducing a color print having an arbitrary dot percent. For this purpose, a large number of samples should be measured to obtain their colorimetry data in advance.